Endobronchial tube apparatus

ABSTRACT

Concepts presented herein include an apparatus for monitoring EMG signals of a patient&#39;s laryngeal muscles. The apparatus includes an endobronchial tube having an exterior surface and two lumens for providing ventilation. Conductive ink electrodes are formed on the exterior surface of the endobronchial tube. The conductive ink electrodes are configured to receive the EMG signals from the laryngeal muscles when the endotracheal tube is placed in a trachea of the patient. At least one conductor is coupled to the conductive ink electrodes and is configured to carry the EMG signals received by the conductive ink electrodes to a processing apparatus.

BACKGROUND

Endobronchial tubes (also known as dual-lumen endotracheal tubes)provide an open airway for patient ventilation during surgery. inparticular, endobronchial tubes are used during surgical procedures toprovide ventilation to individual lungs separately. Currentendobronchial tubes include a first, tracheal lumen and a second,bronchial lumen. Each lumen includes an associated inflatable cuff, thecuff associated with the tracheal lumen being positioned within thetrachea and the cuff associated with the bronchial lumen beingpositioned within one of the bronchus.

SUMMARY

Concepts presented herein include an apparatus for monitoring EMGsignals of a patient's laryngeal muscles. The apparatus includes anendobronchial tube having an exterior surface and two lumens forproviding ventilation. Conductive ink electrodes are formed on theexterior surface of the endobronchial tube. The conductive inkelectrodes are configured to receive the EMG signals from the laryngealmuscles when the endotracheal tube is placed in a trachea of thepatient. At least one conductor is coupled to the conductive inkelectrodes and is configured to carry the EMG signals received by theconductive ink electrodes to a processing apparatus.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view of an EMG endobronchial tube.

FIGS. 2A and 2B are different side views of an endobronchial tube.

FIG. 2C is a sectional view of the endobronchial tube illustrated inFIG. 2A.

FIG. 3 is a partial side view of an endobronchial tube having anelectrode cuff.

DETAILED DESCRIPTION

FIG. 1 shows an EMG endobronchial tube 100 made from extruded polymer.Endobronchial tube 100 includes solid wires 102, a bronchial fitting104, a tracheal fitting 106, a y-connector 108, a bronchial cuffinflating conduit 110, a tracheal cuff inflating conduit 112, extrudedpolymer tube 114, electrodes 116, bronchial cuff 120 and tracheal cuff122. Solid wires 102 are connected to electrodes 116 at aninterconnection 124. Tube 114 transports gases to and from the lungs. Inparticular, tube 114 defines a first, bronchial lumen 126 extending frombronchial fitting 104 to an opening 128 distal the bronchial cuff 120and a second, tracheal lumen 130 extending from tracheal fitting 106 toan opening 132 distal the tracheal cuff 122. The Y-connector 108 fluidlycouples the bronchial fitting 104 and tracheal fitting 106 to bronchiallumen 126 and tracheal lumen 130, respectively.

Fittings 104 and 106 are configured to be connected to a respiratingmachine (not shown) for injecting air into the lungs and withdrawing airfrom the lungs. Cuff inflating conduits 110 and 112 are configured to beconnected to a source of compressed air (not shown) for inflating cuffs120 and 122. Cuff inflating conduit 110 communicates with a lumenlocated in the wall of tube 114, and the lumen communicates withbronchial cuff 120. Likewise, tracheal cuff inflating conduit 112communicates within a lumen located in the wall of tube 114, and thelumen communicates with tracheal cuff 122. During use, one of thefittings (e.g., bronchial fitting 104) is configured to inject air intoone lung while the other fitting (e.g., tracheal fitting 106) isconfigured to injected air into the other lung. For example, cuff 120can be positioned into the left bronchus and cuff 122 positioned intothe trachea. In this case, opening 126 is positioned to direct air intothe left lung from bronchial fitting 104 while opening 132 is positionedto direct air into the right lung from tracheal fitting 106.Selectively, air can be provided to only one of the fittings 104, 106 soas to provide air to only a single lung and collapsing the other lung.In such a case, a surgeon can operate proximate the collapsed lung or onthe collapsed lung. After endobronchial tube 100 is inserted into thetrachea of a patient, electrodes 116 sense EMG signals, which are outputto an EMG processing machine, such as nerve integrity monitor (NIM)device 140, via solid wires 102. Die cut tape may be used to tape tube114 to a patient's mouth to secure the tube and keep it appropriatelypositioned.

In one embodiment, the NIM 140 is configured to determine when theelectrodes 116 are in contact with the vocal folds, and is configured toprovide an alert to the surgeon when such contact is lost. In oneembodiment, the NIM 140 is also configured to determine whether theelectrodes 116 are in contact with muscle or tissue based on thereceived signals

In one embodiment, tube 114 is a braided tube that is more flexible thanconventional solid polymer tubes, and that reduces kinking Tube 114according to one embodiment is formed from a braided polymer or nitinolwithin a thin-walled tube, and reduces or eliminates rotation of thetube at the vocal folds, while allowing a proximal portion of the tubeto rotate.

FIG. 2A shows a first side view (posterior side) of endobronchial tube114 with four electrodes 116. FIG. 2B shows a second side view (rotated90 degrees from the view shown in FIG. 2A) of the endobronchial tube 114shown in FIG. 2A. FIG. 2C is a diagram illustrating a cross-sectionalview of the endobronchial tube 114 shown in FIGS. 2A and 2B.

Electrodes 116 include four electrodes 116A-116D, which are formedaround a circumference of the tube 114 and extend in a longitudinaldirection of the tube 114. Electrodes 116A and 116B are positionedentirely on the posterior side of the tube 114 and are also referred toherein as posterior electrodes 116A and 116B.

Electrodes 116C and 116D are positioned entirely on the anterior side ofthe tube 114 and are also referred to as anterior electrodes 116C and116D. The anterior side of the tube 114 is the bottom half of the tube114 shown in FIG. 2C, and the posterior side of the tube 114 is the tophalf of the tube 114 shown in FIG. 2C. Each of the electrodes 116A-116Dis coupled to a respective trace 150A-150D (trace 150D is not visible inthe Figures). Traces 150A-150D are positioned in a protected (masked)region 152 of tube 114. Posterior electrodes 116A and 116B arepositioned in an exposed (unmasked) region 154 of tube 114. Anteriorelectrodes 116C and 116D are positioned in an exposed (unmasked) region156 of tube 114.

In one embodiment, each of the electrodes 116A-116D has a length ofabout one inch, and extends laterally around a circumference of the tubefor a distance corresponding to an angle 160 of about 60 degrees (i.e.,each of the electrodes 116A-116D has a width of about 16.67 percent ofthe total circumference of the tube). The electrodes are laterallyspaced apart around the circumference of the tube by a distancecorresponding to an angle 160 of about 30 degrees (i.e., the lateralspacing between each of the electrodes 116A-116D is about 8.333 percentof the total circumference of the tube). The posterior electrodes 116Aand 116B are longitudinally offset or displaced from the anteriorelectrodes 116C and 116D. The posterior electrodes 116A and 116B arepositioned closer to the distal end (right side in FIGS. 2A and 2B) ofthe tube 114 than the anterior electrodes 116C and 116D, and theanterior electrodes 116C and 116D are positioned closer to the proximalend (left side in FIGS. 2A and 2B) of the tube 114 than the posteriorelectrodes 116A and 116B.

Tube 114 includes an overlap region 166 where a proximal portion of theposterior electrodes 116A and 116B longitudinally overlap with a distalportion of the anterior electrodes 116C and 116D. The electrodes 116 donot physically overlap each other since they are laterally offset fromeach other. In one embodiment, the overlap region 166 is about 0.1inches long, and the overall length from a proximal end of the anteriorelectrodes 116C and 116D to a distal end of the posterior electrodes116A and 116B is about 1.9 inches. In another embodiment, the overlapregion 166 is about 0.2 inches long, and the overall length from aproximal end of the anterior electrodes 116C and 116D to a distal end ofthe posterior electrodes 116A and 116B is about 1.8 inches. Tube 114 isconfigured to be positioned such that the vocal folds of a patient arepositioned in the overlap region 166. Thus, the configuration of theelectrodes 116 above the vocal folds is different than the configurationbelow the vocal folds. The posterior electrodes 116A and 116B areconfigured to be positioned primarily below the vocal folds, and theanterior electrodes 116C and 116D are configured to be positionedprimarily above the vocal folds. In one embodiment, electrodes 116A and116C are used for a first EMG channel, and electrodes 116B and 116D areused for a second EMG channel.

In an alternate embodiment, all four surface printed electrodes, 112A,112B, 112C and 112D, are equal in length. This will allow the finishproduct to be placed with little concerns of rotational alignment.

As illustrated in FIG. 2C, conduits 110 and 112 are formed in athickness of the tube 114 to carry compressed air to bronchial cuff 120and tracheal cuff 122, respectively. Additionally, inside tube 114 areformed bronchial lumen 126 and tracheal lumen 130. During use, one ofthe lumens 126 and 130 can be used to inject gases into a particularlung while the other lumen is sealed from injecting gases into theopposite lung.

With reference to FIG. 3, another embodiment includes an electrode cuff170 positioned proximal the tracheal cuff 122. In the embodiment of FIG.3, cuff 122 is of a different shape than that illustrated in FIGS. 1-2C.Other shapes for the cuffs 122 and 170 can be utilized. Electrodes 116are applied directly to the electrode cuff 170 and are similar to thatdiscussed above. Cuffs 122 and 170 are sized so as to both providesuitable sealing between the trachea and cuff 122 yet provide suitablecompliance of electrode cuff 170 in contact with the vocal folds of apatient when inflated by pressurized fluid provided within inflatingconduit 110. Upon inflation, the tracheal cuff 122 has a larger diameterD1 than a diameter D2 of electrode cuff 170. In some embodiments, thediameter D2 is selected to be approximately half the diameter D1. In oneexample, D1 is about 20 millimeters, whereas D2 is about 9 millimeters.In yet a further embodiment, D1 is approximately 27 millimeters, whereasD2 is approximately 14 millimeters. Moreover, a length L1 of the cuff170 is selected to be greater than a length L2 for cuff 122. In oneembodiment, the L1 is approximately 1.875 inches. In another embodiment,L1 is in a range from approximately 1.5 inches to 2.5 inches. In afurther embodiment, a ratio of D1:L1 is selected to be in a range fromapproximately 15:100 to 30:100.

Furthermore, a compliance for cuff 170 is selected so as to preventtrauma due to cuff 170 contacting the vocal folds of the patient. In oneembodiment, the cuff 170 is formed of a semi-compliant balloon. Thesemi-compliant balloon will increase in diameter about 10 to 20 percentfrom a nominal pressure to a rated burst pressure for the balloon. In afurther embodiment, cuff 170 is formed of a compliant balloon such thatthe balloon will increase in diameter from 20 to 200 percent from anominal pressure to a rated burst pressure of the balloon. In a furtherembodiment, the cuff 170 is formed of a compliant material that has agreater compliance than a material selected for cuff 122. In oneembodiment, cuff 122 has a compliance defined as increasing in diameterabout 20 to 200 percent from a nominal pressure to a rated burstpressure for the cuff 122.

Inflating conduit 110 extends along the length of tube 114 to electrodecuff 170 and continues in extension to the tracheal cuff 122. Due torelative compliance of the cuffs 122 and 170, cuff 122 is configured tofluidly seal the trachea of a patient when positioned, whereas electrodecuff 170 inflates to contact the vocal folds of the patient so as toprevent trauma from occurring due to contact between the cuff 170 andthe vocal folds. Furthermore, by selecting diameters D1 and D2 of cuffs122 and 170, tension exerted on an exterior surface of each cuff isadjusted. In one embodiment, thickness and diameter for cuffs 122 and170 are selected such that cuff 122 will absorb pressure and reducepressure on cuff 170. In this configuration, cuff 170 can conform to ashape of vocal folds and ensure sufficient electrical contact betweenthe electrodes 112 and the vocal folds without causing irritation byexerting too much pressure on the vocal folds.

Although the present disclosure has been described with reference topreferred embodiments, workers skilled in the art will recognize thatchanges can be made in form and detail without departing from the spiritand scope of the present disclosure.

What is claimed is:
 1. An apparatus for monitoring electromyographicsignals of a patient's laryngeal muscles, comprising: an endobronchialtube defining first and second lumens; a first cuff coupled to theendobronchial tube and positioned proximate a first opening fluidlycoupled with the first lumen, the first cuff sized to be positionedwithin a bronchus of the patient; a second cuff coupled to theendobronchial tube and positioned proximate a second opening fluidlycoupled with the second lumen the second cuff configured to bepositioned within a trachea of the patient; and conductive inkelectrodes positioned on an exterior surface of the endobronchial tubeand proximate the proximal cuff
 2. The apparatus of claim 1, wherein theelectrodes include four electrodes positioned around a circumference ofthe exterior surface.
 3. The apparatus of claim 1, further comprising aY-connector coupled to the endobronchial tube, the Y-connector fluidlycoupling first and second fittings to the first and second lumens,respectively.
 4. The apparatus of claim 1, further comprising aninterconnection coupled to the tube and conductive traces electricallyconnecting electrodes with the interconnection.
 5. The apparatus ofclaim 1, further comprising first and second inflating conduits fluidlycoupled to the first and second cuffs, respectively.
 6. The apparatus ofclaim 5, wherein the exterior surface includes an electrode cuff fluidlycoupled to the second inflating conduit and having the conductive inkelectrodes positioned thereon.
 7. A method for monitoringelectromyographic signals of a patient's laryngeal muscles, comprising:providing an endobronchial tube defining first and second lumens, theendobronchial tube including conductive ink electrodes positioned on anexterior surface thereof; positioning a bronchial cuff within a bronchusof the patient, the bronchial cuff being coupled to the endobronchialtube; positioning a tracheal cuff within a trachea of the patient, thetracheal cuff coupled to the endobronchial tube; and measuring signalsof the patient using the conductive ink electrodes.
 8. The method ofclaim 7, wherein the electrodes include four electrodes positionedaround a circumference of the exterior surface.
 9. The method of claim7, further comprising: coupling a Y connector to the endobronchial tube,the Y connector fluidly coupling first and second fittings to the firstand second lumens, respectively.
 10. The method of claim 7, furthercomprising electrically connecting the electrodes to an interconnectionon the endobronchial tube with conductive traces.
 11. The method ofclaim 7, further comprising: inflating the first and second cuffs usingfirst and second inflating conduits, respectively.
 12. The method ofclaim 11, further comprising: providing an electrode cuff fluidlycoupled to the second inflating conduit and providing the conductive inkelectrodes on the electrode cuff